In April of last year, members of Russian feminist punk band Pussy Riot were sentenced to two years in prison on charges of “hooliganism motivated by religious hatred or hostility.” Now, a little over a year later, Nadezhda “Nadya” Tolokonnikova and Maria “Masha” Alekhina still remain behind bars, while the band’s other member who was arrested, Yekaterina Samutsevich, has been set free.

Tolokonnikova and Alekhina will soon face another round of parole hearings and in anticipation of this, Amnesty International has organized a petition calling for their immediate release. The group has also enlisted a handful of music’s biggest names to sign the petition and join them in this crusade. Adele, Radiohead, Arcade Fire, Coldplay, U2 and Sir Paul McCartney are just some of the musicians who’ve already pledged their support. You can read their full letter below, and, as Stereogum points out, sign the petition for yourself here.

AMNESTY INTERNATIONAL OPEN LETTER

Dear Masha and Nadia,

As the one-year anniversary of your trial approaches, we are writing to assure you that, around the world, people are both still thinking of you and working for your release. Although you were the most visible of the protesters, we know that there were many other young people who have suffered in the protests, about whom we are also very concerned. But, in many ways, through your imprisonment, you have come to represent them.

Many artists voiced their concern when these charges were first brought against you, we had every hope that the authorities, in dealing with you, would show some understanding, a sense of proportion, even some of the wonderful Russian sense of humour, but none of the above were forthcoming.

The impact of your shockingly unjust trial and imprisonment has spread far and wide. Especially among your fellow artists, musicians and citizens around the world, including the many parents who feel your anguish at being separated from your children. While understanding the sensitivities of protesting in a place of worship, we ask that the Russian authorities review these harsh sentences, so that you may return to your children, your families and your lives.

The right to freedom of expression and dissent is a legitimate one and essential in any kind of democracy. You have been accused of what could be described as ‘a victimless’ crime, but in our opinion, in a just society, there can be no crime where there is no identifiable ‘victim’.